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IMPROVBD DRAW-BRIDGE.

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T0 ALL WHOM IT MAY CONGERNi Be it known that I, C. K. MARSHALL, of the city of New Orleans, parish of Orleans, and Stute of Louisiana, have invented a new and useful Improved Draw-Bridge; and I do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon, and making part of this specification, in which Figure lis a side elevation,

Figure .2 is a plan view, and

Figure 3 is an enlarged transverse section.

The n ature of my invention consists in the combination of a movable ear or cars, platform or platforms, suspended by rods, chains, or their equivalents, and (properly braced to prevent lateralmotiom) thus forming travelling-trucks, which run upon rails laid on the top of tubes of metal,'or upon trusses of iron or wood, which tubes or trusses are supported upon pillars, and which servealso asviaducts, either through the tubes, or on or between the trusses, and thus by this combination the means of crossing streams are afforded to the traic and travel, either at a. low'level, coincident withthe heavy business, or at the elevated point for 4railroad-ears, or other methods of transit, and for passengers either in wagons, carriages, or as pedestrians; the tubes or trusses being elevated at such a height above the stream, that the vessels used in commerce can freadily pass under, and thus the navigation of the stream will not be interrupted, and the platforms or cars suspended, are so admirably arranged and Vworked by machinery, that there will be no delay tothe navigation, and when these ears are closed., it offers aicontinuous bridge below the main viaduct above.

These cars or platforms are covered to attord protection from the weather whilepassengers are upon them, and are in fact suspended wherries moved by stationary engines; and in situations where the navigation is steady, these whcrrics will move across, and their moving will be the normal condition. In other places, where the crossing is greater and navigation less, they can be located and-form a continuous viaduct, to be moved only when vessels arelto pass, byvvhich arrangement the business of a community canbe readily facilitated by' the accommodating circumstances of my invention. Outside of the tubcsor trusses, I provide on' each side for afoot-passenger track. And as in somo situations the upper bridge will be much above the le'vel of'the surface lof the ground, in such eases I descend by long slopesV erected upon light piers, which slopesare for the wheeled vehicles, and by lwinding-stairs which can be conveniently located to suit the concomitant circumstances. In places where the approaches are elevated, I providefor a connection of these to the bridge on either side by any usual structurcfor spanning long openings, and from which branches may be led oti to-various roads or streets, connecting with the main avenue.

Where the trathc is heavy, and tlie'communities to be accommodated are very extensive, requiring long 4spans and heavy cars, or platforms, or when-ics, I run up the piers above the tubes or trusses, andform vtowers in which I locate the engines andimachinery for operating the cars or platforms by endless chains. AWhen tubes are used in addition tothe t-wofootways, one on each side, I providcalso two footways above, on the top of the tubes, thus giving ample facilities for the pedestrians in crowded cities.

In Ithe drawing, A A are the tubes; B B, the trusses, either of which can be used; C C C, the piers; D I), the opposite sides of the stream; E E, the travelling-cars or platforms, suspended by rods e, and braced ,by diagonal rods c F F, the landings on each side, having movable browsff, to 'reach from the ears to the landing; G, the girder; a a a, the., arethc trucks; a' n. a', the large wheels of trucks; b b, frictionro'llers on the frame of the travelling-cars, which travel against rods on-the insides ofthe tubes, to prevent swinging from theactlon of high winds; c e,rai]roadcurs; d d, the centro where the cars moet; c e, the suspension-rods, whichare made fast to .thc girdcrs G; c "c, the diagonal braces. i l

I am'aware that movable platforms have been used with timber trusses, and moved on trucks which operate upon bracketed supports, but I do not know of any such combinations as these proposed, viz, to support the tracks upon thc topA of a tubo-or truss, by spanning the openingvbctween with a girder of any form suiicxent to wil-{esi- 2 support the suspended weight, and also to stiien the cnrs laterally by friction-rollers on the sides of the frame which bear upon the supporting structure. l

Having thus fully described my invention,.what I claim as new therein, and desire to secure by Letters Patent of the United States, is-

Theconstruction and arrangement of the travelling-trucks a a, with suspended platforms E E, when the same is supported, braced, and guided, as herein described, and combined with the tubular bridges AA, the whole supported on piers, in the manner and for the purpose herein described.

In testimony whereof, I have signedmy name to this specification in the presence oftwo subscribing witnesses.

o'. K. MARSHALL.

Witne'sses J oHN. D.- BLooR, EDWIN JAMES. 

